An audio and video signal transmission line is used to transmit an audio signal or an audio and video signal output by a device such as a computer and a smart mobile terminal to a user or another device. The audio and video signal transmission line includes an earphone with wires and an audio and video data line. The earphone with wires is classified into an LRG earphone, an LRMG earphone, and an LRGM earphone according to different line sequences. The LRG earphone includes two sound channels, a left one and a right one; the LRMG earphone and the LRGM earphone both include left and right sound channels and a microphone.
During the implementation of the present invention, the inventors have found that the prior art has at least the following problem:
At present, a device connected to an audio and video signal transmission line supports only an audio and video signal transmission line that matches the line sequence of the interface of the device, which cannot achieve compatibility between different types of devices and audio and video signal transmission lines.